1. Field of the Invention
The present invention relates generally to a brushless DC motor driving circuit, and more particularly to a brushless DC motor driving circuit which enables the DC motor to be simple in construction.
2. Description of the Prior Art
A brushless DC motor having a plurality of switching transistors has been already proposed. With such a prior art brushless DC motor, the rotating state, i.e., rotary phase, of the rotor of the motor is detected by a detecting element such as a magneto-sensitive element, a photo-sensitive element or the like, and a plurality of switching transistors are successively switched with the output from the detecting element, and a current is applied successively to a plurality of motor windings to rotate the rotor.
In such a prior art brushless DC motor driving circuit above described, it is troublesome to install the detecting element which detects the rotary phase of the rotor. Further, the rotary state of the rotor is influenced a great deal in accordance with the position-adjustment of the detecting element attached to the motor.